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Table of Contents

  1. Topic pack - Marketing - introduction
  2. 4.1 The role of marketing - notes
  3. 4.1 The role of marketing - questions
  4. 4.2 Marketing Planning - notes
    1. Marketing planning
    2. The marketing mix
    3. The Total Product Concept
    4. Ethics of marketing
    5. Marketing audit
    6. Porter's five forces
    7. Porter's five forces - activities
    8. Marketing objectives
    9. Market research - introduction
    10. The role of market research
    11. Primary and secondary research
    12. Primary research - information gathering techniques
    13. Observations - case studies
    14. Group-based market research
    15. Market research - summary
    16. Questionnaires
    17. Sampling
    18. Methods of sampling - introduction
    19. Main methods of sampling
    20. Sampling errors
    21. Market segmentation
    22. Consumer Profiles
    23. Types of segments
    24. Demographic segmentation
    25. Psychographic segmentation
    26. Psychographic segmentation - case study
    27. Geographic segmentation
    28. Industrial markets
    29. Targeting
    30. Positioning
    31. Corporate image
    32. Position/perception maps
    33. Unique selling point/proposition USP
    34. Marketing strategies and tactics
    35. Sales forecasting
    36. Qualitative forecasting/data
    37. Forecasting and correlation
    38. Forecasting techniques
    39. Constructing time-series analysis
    40. Moving average
    41. Four point moving average - worked example
    42. Identifying the seasonal variation
  5. 4.2 Marketing planning - questions
  6. 4.3 Product introduction - notes
  7. 4.3 Product - questions
  8. 4.3 Product - simulations and activities
  9. 4.4 Price - notes
  10. 4.4 Price - questions
  11. 4.4 Price - simulations and activities
  12. 4.4 Promotion - notes
  13. 4.5 Promotion - questions
  14. 4.6 Place (distribution) - notes
  15. 4.7 International marketing - notes
  16. 4.7 International marketing - questions
  17. 4.8 E-commerce - notes
  18. 4.8 E-commerce - questions
  19. Printable version

Main methods of sampling

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A common student mistake...

Do not mix up random and convenience samples. Selecting the first ten people who enter a shop is not a random sample as every member of the population (potential customers) the firm is interested in does not have an equal chance of being selected - only those entering the shop stand a chance of being chosen. Indeed, those buying from this shop may have similar characteristics not shared by others in the sampling frame.

This mistake is often made by students in their internal assessments and extended essays when surveys are carried out. It is often written that:

'I chose the first ten people at random'.

This is not an accurate description of a random sample, but of a convenience sample.

Sample size

How many respondents should be in a sample? This is the realm of statistics, and it will be touched on later. The answer, though, is likely to be 'fewer than you think'. Political public opinion polls seeking voting intentions of several million voters are based on samples of approximately 1,000. They are also based on careful stratified sampling methods. They make predictions with claimed accuracy of about +/-2%. Not a bad accuracy for such a small sample.

How questions are phrased is critical to the accuracy of the results. The use of leading questions will clearly affect the survey's reliability. Questionnaires can be designed to get a specific result, so the developers need to be careful.

Methods of asking questions

There are many ways to conduct research as has been discussed earlier. These include:

  • Unstructured interviews
  • Structured interviews
  • Questionnaire
  • Telephone survey
  • Consumer panels
  • Focus group

The validity of the result will be determined by how many people are asked, how they are selected and the nature of the questions. We looked at many of these methods in the previous section.

Matching sampling method to population

It is important to match the sampling method used to the nature of the population being considered. If, like a school, the population is all in one place then the options are different to a situation where the population is geographically scattered (e.g. an online store of some sort). The table below summarises some of these options:

Nature of population Sampling methods available Sampling methods not available
  • Population all lives in a single location (e.g. a local retail store)
  • Simple random sampling
  • Systematic sampling
  • Stratified sampling
  • Population geographically scattered (e.g. online store)
  • Multi-stage sampling
  • Cluster sampling
  • Population is split into categories (e.g. a target market of a specific age-group)
  • Stratified sampling
  • Quota sampling